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Publication numberUS823576 A
Publication typeGrant
Publication dateJun 19, 1906
Filing dateDec 30, 1903
Priority dateDec 30, 1903
Publication numberUS 823576 A, US 823576A, US-A-823576, US823576 A, US823576A
InventorsCraig R Arnold
Original AssigneeCraig R Arnold
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process of extracting metals from their ores.
US 823576 A
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Description  (OCR text may contain errors)





No. 823,576. v

. Specification of Letters Patent. i

Patented Tune 19, 1906.

. n ion fil d'Deceniber 30,1903. Seria1No. 187,096.

Be it known that I, CRA GR. AR OLD, a

citizen of the United State's, and a resident of Philadelphia, in the county of Philadelphia and State of Pennsylvania, haveinvented a certam new and useful Improvement in Processes of Extracting Metals from their Ores, of

which the following is a specification. 7 My invention relates to those processes of recovering gold, silver, and other precious metalsjknown as the cyanid process and in which the ore or other metal-bearing sub- -stancemo1stenedor mixed with cyanidsalt is subi'ected to the action of an oxidizing agent ike air.

The object of my resent invention is to overcome the'diflicu ties and objections to this process as-heretofore conducted either. by. forcing airunder plenuminto the tank containing the ore to agitate the same orby the use of mechanical'stirrers working in the pulp while 'the body. of pulp is exposedto In the process as hereto-' fore conducted there is liability the atmosphere.

to the escape of hydrocyanic gas or. 7 other 'deleterious gases even though the proces s is conducted 1n a closed vat or tank, for the reason that when the air or gas is forced under plenum into the tank the pressurebeing higher than thflOlltSldQ atmospheric pressure any dam-- age .or leak in the outlet-plpes will permit the' esca e of thedeleterious gases.

y invention has for its obi'iect not only to Y thoroughly remove the possi ility of esca e of the hydrocyanlc-acid gas or any other de eterious gases into the atmosphere, but to also 'hasten the process; to which end'my invention consists -'in the novel process or method of treating ores by 'o-the cyanid process by maintainlng a vacuum at the outlet of a closed'tank'in which a pulp of the ore and a cyanid solution is, contained, and therebv drawingair into the lower portion of the body of pulp in sufficient volume and at ai roper polnt to thoroughly agitate the body 0 pulp,

said 'air being passed first through a genera tor adapted to furnish a halogen gas and finally passing the gases removed fromthe tank, by the exhaustion process through an absorption tank or vat and through a falling esca efto theatmos'phere.

body of Water before they are permittedto eatly indevelop; fifth, I by the use of a hydraulic vacuum-pump the waste gases may be caused to commlngle with the waste waters and pro duce a harmless compound sixth, should any leaks occur they can be readily stopped from the outside. a

I 'In carrying out invention I prefer to employ the novelcombination of apparatus hereinafter described and which is made the subject of an application for patent filed by me as a division of the resent alpplication.

The accompanying (ii grammatically aniapparatus suitable for can rying on the process" of treating the ore ma partlal vacuum.

5 indicates thetreating'tank or vat, which may be of any desired form and is provided with a ho perthrough which the tank may be char ed 7 indicates the discharge-opening, through possl le to disawingi inflates-di "The advantages attendant upon my im First, the 7 5 harm; fourth, t e treating-tank may be still used for an .indefinitetime even after leaks which the treated pulp is emptied into a setj tling tank 15 or otherwlse removed for re-. Y

vcovery metallic constituents thereof. p

Thetank is preferably made of conical form at its bottom to assist in the discharge of the,pulp and, further, to facilitate the movement 'of the-mass of pulp under the ac tion of the stream of gasintroduced into the mass of the pulp at the lower end of the tank through p'pe 25, having a suitable opening or openings within the tank or vat. r

' 26 is asuitable pi e opening into the gas of the solution-and separation of the space at the top -o the tank and through which the gas or gases therein are removed b suction produced by the actionofa suitable pump, the function of which is to maln tain a partial vacuum'inthe tank 5.

Thepipe 25 'comrnunicateswith any source of 'air or as the pressure of which is prefer- 1 ably-not 'gher than atmos heric'pressure,

.so that,-'as will be obvious, t e operation of the vacuum-pump connected with pipe 26 will serveto produce a partial vacuum in the ;tank 5 and will induce the flow of gas by I 45 unite wither absorb hydrocyanic acid, thus producing a simple cyanid suction through into the pot pulp in the tank 5.

As a means for maintaining a partial vacuum in the treatin tank and pipe 26 or other passages by which the excess or waste gases are conducted awa I prefer to employ a vacuum-pump 9, w ch may be of the Wellown Sprengel t ated by water con sure by a pi said water e and preferably operucted thereto under res- By the use of a vacuum-pump of the water submerged, as detype having its outlet scribed, I secure the advantage that the waste or excess gases passing from pipe 26 to and through the pump will commlngle with the waste water and produce a harmless compound. Ordinarily, however, I prefer to interpose between the pump and the tank one or more absorption vats'or tanks 8 of the ordinary type, in which the gas is caused to pass through p a solution of material suitable chemically uniting with the gas or gases taken from the tank, and s9 operating e ther to render the same harmless or to recover the same in suitable form to permit'the recovered elements to be again employed in the treatingank. Thus, for instance, in the cyanid process said absor tption-tanks 8 might I treatin I gas, which is 'drawn up the tank and which agitates the same. The 4 contain a material suita le for uniting with the hydrocyanic-acid gas generated 1n the -tank, in which case they would be prefera ly charged with some caustic fsolution, such as a solution of caustic soda, caustic lime, caustic otash, or any other caustic alkali or alkaline earth adapted to adapted to act as a solvent for gold, silver, or other metal-bearing ore or pulp undergoing treatment in the tankorvat5.

' The oxidizing agent-is obtained by drawing atmospheric air by suction into the tank at the bottom thereof through the pipe 25, such air being caused to first pass through a suitable solution contained in" the Woulfe bottle or tank 4 and of suitable character for generatin bromin or other halogen element'which'lt may be desired to use'asthe reducing gas or agent. The oxygen of the air constitutes the oxidizing element of the thro%h the pulp into generating material may be introduced into the bottle 4 through the funnel 13. Said bottle is preferably 0 glass, so. that the quantity pipe 25 and up through the coil 2 in e provided with a stop-coc 10,

scribed the the possibility of lea of such material can be observed. Preferably the air introduced into said bottle through a heater 3,and the pipe 1 may be provided with an inlet-funnel 14 for the introduction of any. oxidizin or reducing agent. It willbeunderstoo also that the contents of the bottle 4 may be such as to produce other oxidizing or reducing agents besides bromm. Also, as will be obvious, when-bromin is employed the absorptiontank 8 may be charged with a solution of al kali, which will combine with the bromin or other gas of the halogen group that may-be passed through the pulp and escape by the pipe 26.

In the operation of the apparatus depulp in the tank 5 is mixed with a sufllcient amount of solution to render it capable of being agitated or stirred by action of the gases drawn u through the same from the pipe 25 to t e space with i ipe 26 communicates, and in which space the partial vacuum is maintained, as already described. I It willbe seen that in my process the operation is not conducted under pressure of gas used for agitation, but under a partial vacuum in ractically all the pipes or spaces in which the gas exists, whose esca e is thus reventedeven though there shou d be a deect or opening through which leakage would otherwise occur. ThlS advantage applies obviously to the inlet as well to the.'ex1t pipe or space wherein the excess or'waste ases resulting from the treatment, exist. oreover, it will be seen that by my rocess I thoroughly eliminate the possib' ities of the'escape of any deleterious gases into the atmosphere, because those gases, like hydrocyanic gas, which are drawn from the upper part of the tank are caused to pass through the abso tion-tank containing the caustlc solution an are thereby absorbed, While if by chance the said solution should fail to completely take up such gas the same, to ether wlth any other deleterious gases, will e taken up in the water column through which the can only ass to the external atmosphere, ence, as be seen, I not only obviate the objections incident to the recess and arising from kag'e or of escape of the deleterious gases freely into the atmos here at the final outlet of the system, but also am enabled to conduct the process in a thoroughly economical and efficient manner, be-

cause, first, the'pulp is thoroughly'a 'tated by the oxidizing air, while, secondly, t e hydrocyanic gas evolved the process is recovered and goes to make a cyanid salt useful inthe' operation. I

What I claim as my invention is pipe 1 is carried through the heater- 1 'The'herein-describedprocess of recovering gold and silverfrom ores by the cyanid consisting in drawing air by'suctioli;

first, through a generator of ahalogen gas, then through a pulp containing the cyanid salts and in sufiicient volume to thoroughly agitate the" same and finally carrying the waste and resultant gases-from the tank, first through an absorption tank or vat and then through a column of liquid before permitting any escape to the external atmosphere.

2. The herein-described improvement in recovering metals by the cyanid rocess, consisting in maintaining a partia vacuum in thegas-space above a. pul-p of the ore and a cyanid salt while contained in a suitable closed vessel, introducing air by the exhaust action thus produced in suflicient amount beneath the body of pulp to thoroughly agitate the same, passing the esca e or waste gases passing-from the tank by t e vacuum main' tained, through a caustic solution and finally delivering the remaining gaseswhich pass through'such solution, to a column of Water employed in maintaining the vacuum.

the vacuum 'maintame therein, t

v v3. The herein-described improvement in recovering metals by the cyanid process consisting informing a pulp of the ore and a solution of a cyanid salt, agitating the pulp While contained in a closed vessel by drawing air through a'heater and a generator of a halogen-gas and thenthrou-gh thebody of pulp by maintaining a partial vacuum the gasspace above the pulp-body and passing the gases evolved in the pul -contain1n tank' by ough a draulic t gases exhausted from the space above the pulp to a regenerating solution and to a column of water which maintainsthe vacuum,

said solution and'column being'in series with one another.

5. The -'h erein-described process of recover mg precious metals, consisting in forming a pu p of the ore and a cyanid solution, maintainingthe vacuum above the body of pulp by drawing air,-first, through a heater and 'then through a generator of a halogen element, and finally throughthe body of pulp in sufiicient quantity to agitate the same and delivering the air or gases exhausted from the tank to a column of liquid by which the vacuum is maintained.-

Signed at Philadelphia, in the county of Philadelphia and State of Pennsylvania, this 60 I 21st day of December, A.- D. 1903. a

CRAIG R. ARNOLD. Witnesses:



Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4994243 *Oct 21, 1988Feb 19, 1991Cyprus Minerals CompanyEvaporation of hydrogen cyanide from pH-controlled solutions, then basification; recovering metals from ores
US5078977 *Oct 20, 1989Jan 7, 1992Cyprus Minerals CompanyCyanide recovery process
US5169615 *Oct 30, 1990Dec 8, 1992Jennings Melvin AAcidifying slurry containing metal cyanide complex, then treating with sulfide, basification to purge hydrogen cyanide; recovering precious metals
US5254153 *Jan 6, 1992Oct 19, 1993Cyprus Minerals CompanyCyanide recycling process
WO1990004655A1 *Oct 20, 1989May 3, 1990Cyprus Minerals CoCyanide recovery process
Cooperative ClassificationC22B11/08